Question

the animation shows how dolphin development provides a clue to understanding the evolution of vestigial hind - limbs in whales. complete the following passage.

scanning a dolphin embryo highlights its evolutionary history. early in dolphin development, both fore and hind - limb buds form. while the forelimb buds continue to develop into flippers, the hind - limb buds disappear. the genes that are normally active in the hind - limb buds of four - limbed animals are turned off. a genetic change leading to the silencing of a trait during development may have been an important milestone in whale evolution.

Explanation:

Dolphin development reveals evolutionary history. Limbs form early, forelimbs become flippers and hind - limb buds disappear due to genetic changes.

Answer:

embryo; flippers; disappear; genes; genetic